1. Field of the Invention
The present invention relates to a film deposition apparatus and a film deposition method that deposit a thin film on a substrate.
2. Description of the Related Art
An ALD (Atomic Layer Deposition) method is known, for example, as one of the methods of depositing a thin film such as a silicon oxide film (i.e., SiO2) on a substrate such as a semiconductor wafer (which is called a “wafer” hereinafter), as disclosed in Japanese Patent Application Laid-Open Publication No. 2011-40574. In this apparatus, five wafers are arranged on a turntable in a circumferential direction, and a plurality of gas nozzles is arranged above the turntable. The apparatus deposits a reaction product on the wafers in a layer-by-layer manner by supplying a plurality of kinds of reaction gases that react with each other on the respective rotating wafers. Moreover, in the apparatus, a thin film is densified by providing a member for performing a plasma modification at a location away from the gas nozzles in the circumferential direction and by performing the plasma modification process to each reaction product deposited on the wafer in a layer-by-layer manner.
However, a dense thin film may not be deposited to the degree of meeting required specifications, depending on the type of device on which such a silicon oxide film is deposited, even though the plasma modification is performed. More specifically, when a concave portion having a high aspect ratio that exceeds, for example, dozens or one hundred, such as a hole or a groove (i.e., trench) is formed in a surface of the wafer, a degree of the modification may vary in a depth direction of the concave portion. In other words, when such a concave portion with the high aspect ratio is formed, the plasma (which is more specifically, argon ions) is unlikely to go into the concave portion. Moreover, because the plasma treatment and the film deposition process are performed together in a vacuum chamber, a process pressure in the vacuum chamber is higher than a vacuum atmosphere in which the plasma can remain active preferably. Due to this, the plasma is likely to be deactivated when the plasma contacts an inner wall of the concave portion, which also causes the degree of modification to vary in the depth direction of the concave portion.
Japanese Patent Application Laid-Open Publication No. 2010-245448 discloses a configuration that provides a heat lamp to perform an annealing treatment in a location away from each nozzle in a circumferential direction in such an apparatus, but specific film quality of a thin film is not considered. Japanese Patent Application Laid-Open Publication No. 10-79377 discloses a device that performs a modification treatment together with a film deposition process, but the above-mentioned problem is not described.